Head restraints are known which are removable from the backrest of the seat to enable better driver or passenger visibility. The front passenger head restraint may be electrically moveable to maximise customer comfort and also may be electrically foldable as to allow improved vision for customers seated in the rear of the vehicle, for example when being chauffeur driven. The head restraint may even be removable to further improve the visibility for the passenger seated in the rear of the vehicle.
However, with the advent of additional features optionally mountable in head restraints, such as speakers or video display equipment, or motors for electric movement, the mass of head restraints is becoming more significant. In such cases, the mounting arrangement needs to be more secure than when such options are not included, so as to avoid the head restraint from being detached as a result of a sudden deceleration of the vehicle during a crash and, rather than being a safety feature of the vehicle, instead possibly becoming a safety hazard.
A conventional mounting arrangement for a head restraint comprises a metal shoe welded on the end of each of two arcuate tubular mounting rods depending from a head restraint body. A plastic sleeve is clipped around each shoe and is adapted to fit in a metal bracket of a bracket assembly installed in a backrest of a seat of a vehicle. The sleeve acts as a cushion between the two metal components (shoe and bracket). A selectively displaceable hook retains the shoe in position, securing the shoe and sleeve, and thus the rods and head restraint, in engagement with the bracket of the bracket assembly. A manoeuvring mechanism forms a part of the bracket assembly to enable the bracket to be adjusted and hence the position or orientation of the head restraint to be altered. In one case, the bracket is rotatably mounted in the bracket assembly, whereby the head restraint can be tilted forwardly. In addition, the hook may be displaced, by selective user actuation, whereby the shoe is released from the bracket and can be withdrawn therefrom in an axial sliding “unplugging” movement, whereby the head restraint can be withdrawn and separated entirely from the seat.
The seat may have apertures in its top edge, through which the rods extend, in normal use and orientation of the vehicle and its seating, in an approximately vertical direction. The rods join with the head restraint body above the top edge of the seat. Below the top edge of the seat, after passing through the apertures, the rods may be arranged in an arc, centred on the centre of rotation of the bracket. The shoes of the rods plug into the bracket by movement therebetween in an approximately horizontal direction, the arc of the rods being approximately a quarter of a circle. When in a first configuration of the head restraint, the rods extend approximately vertically out of the top edge of the seat back rest and the body of the head restraint is above that back rest in a normal position to support and protect a passenger's head and neck when seated in the seat.
When the bracket is rotated by actuation of a motor or other means, the arced section of the rods progressively exit the apertures, tilting the head restraint body forwardly of the seat into a second configuration, lowering its top edge. In moving to this second configuration, the shoes of the rods may be withdrawn from the bracket in an approximately vertical direction, through the apertures, once the bracket has been rotated through approximately ninety degrees, and once the hook, or other mechanism retaining the shoes in place in the bracket, has been released by the user.
Throughout this specification the description of components, parts or assemblies being approximately vertical, approximately orthogonal or approximately horizontal is not intended to be unduly limiting but are employed simply to indicate to the reader relative positions, in general terms, of those components, parts or assemblies. The precise geometry of the parts so described is a matter of design choice.
Thus, in normal use of the head restraint, the shoes and sleeves are approximately horizontally disposed in the bracket, with the rods extending approximately vertically out of the seat apertures. Should the vehicle in which the seat and head restraint are fitted be travelling at speed and be involved in a frontal (or rearward) collision, and decelerate (or accelerate) violently in a forward (or rearward) direction of the vehicle, the head restraint will apply a load on the shoes in the bracket. Should the head restraint be heavy (for example as a result of additional features such as speakers or video display equipment being mounted thereon), the load applied may be sufficient to snap and crush the plastics sleeve between the shoe and bracket and permit an unintended degree of freedom of movement between the shoe and bracket. Such unintended freedom of movement between the shoe and bracket can result in the hook or other means normally restraining the shoe in place becoming dislodged and permitting the shoe to separate from the bracket, potentially resulting in the headrest separating from the seat and becoming a projectile within the vehicle.
It is an object of embodiments of the invention to at least mitigate one or more of the problems of the prior art.